Year	U.S. dollars (Units)
1980	6251.855
1981	5886.037
1982	6077.801
1983	5839.504
1984	5591.496
1985	5934.214
1986	7992.700
1987	9418.976
1988	10364.701
1989	10754.010
1990	13644.023
1991	13747.422
1992	15331.031
1993	14261.995
1994	15454.484
1995	19085.723
1996	20780.222
1997	22467.346
1998	24201.139
1999	26231.627
2000	26184.759
2001	28119.377
2002	32481.584
2003	40939.729
2004	47388.915
2005	50476.482
2006	53738.836
2007	60770.189
2008	60989.842
2009	51943.659
2010	48620.625
2011	52159.122
2012	48918.729
2013	51422.864
2014	55651.915
2015	62027.390
2016	62556.102
2017	69863.657
2018	79182.663
2019	80608.825
2020	85776.894
2021	101965.621
2022	103290.607
2023	104272.075
2024	106058.582
2025	109153.379
2026	112706.213
2027	116359.347
2028	120220.224
2029	124201.410